Project Summary The Hospital for Sick Children (SickKids), in Toronto Canada, is one of the largest children?s hospitals in North America, with a world-renowned program in heart diseases in children. The SickKids Labatt Family Heart Center is a leader in research in heart disease in many areas; especially in large research studies that require the high recruitment of specialized patient populations. SickKids has been an active and productive member of a group of child heart disease research centers called the Pediatric Heart Network (PHN) since its inception 15 years ago. SickKids is an excellent team member for this network in terms of recruitment of patients and getting high quality results. SickKids members have greatly contributed to the PHN?s research into congenital heart disease and acquired heart disease, and now will lead one of the studies. It has many special features that help it to contribute to the studies, and also some special new initiatives that can help the network to move in new directions.